Changes in the leaf composition, leaf mass and leaf area during leaf senescence in three species of mangroves

Dynamics of leaf mass, leaf area and composition during leaf senescence wer e investigated in three mangrove species: Kandelia candel (L.) Druce, Brugu iera gymnorrhiza (L.) Lamk. and Rhizophora stylosa Griff at Jiulongjiang Es tuary in Fujian, China. Differences in nutrient retranslocation efficiencie s (RE) during leaf senescence on composition (milligrams element per gram, mg/g dw), content (milligrams nutrient per leaf, mg/leaf) and leaf area (mi lligrams nutrient per square centimeter leaf, mg/cm(2)) were compared. Duri ng leaf senescence, large amounts of N, P and K were retranslocated out of senescing leaves, while Cl, Na, Ca and Mg accumulated in senescing leaves. RE on the basis of composition or leaf area would underestimate retransloca tion. During leaf senescence, there were significant decreases in leaf mass and leaf area in K. candel and R. stylosa, while B. gymnorrhiza changed li ttle. (C) 2001 Elsevier Science B.V. All rights reserved.